Advisories for Npm/@Sveltejs/Kit package

Applications using enhanced form actions (use:enhance) on routes that accept paths beginning with //, such as catch-all routes, may be vulnerable to an open redirect.

Applications that prerender pages and use setHeaders to set a cache-control header from an untrusted source are vulnerable to cross-site scripting (XSS). SvelteKit inserts the header value into a <meta http-equiv="cache-control"> tag without escaping it. An attacker who can influence this value at prerender time can break out of the content attribute and inject HTML or JavaScript into the generated page. The injected code can then execute when users visit …

SvelteKit is vulnerable to remote CPU-exhaustion DoS attacks via specifically-crafted Accept headers. The impact is mitigated by default header length limits on most platforms, but in the case of raised or absent limits a denial of service is possible.

If you use remote form functions, have an input field of type file, and accept arbitrary user-controlled path names for the field, then you are vulnerable to a prototype pollution attack where the attacker can remove e.g. methods on the prototype.

Big remote form function payloads can cause the Node process to crash. Doing this repeatedly can cause DoS.

query.batch() could, under very rare and specific timings, cause concurrent requests from different users to merge and resolve under single request context, enabling cross-user data disclosure.

redirect, when called from inside the handle server hook with a location parameter containing characters that are invalid in a HTTP header, will cause an unhandled TypeError. This could result in DoS on some platforms, especially if the location passed to redirect contains unsanitized user input.

Under certain circumstances, requests could bypass the BODY_SIZE_LIMIT on SvelteKit applications running with adapter-node. This bypass does not affect body size limits at other layers of the application stack, so limits enforced in the WAF, gateway, or at the platform level are unaffected.

Some relatively small inputs can cause very large files arrays in form handlers. If the SvelteKit application code doesn't check files.length or individual files' sizes and performs expensive processing with them, it can result in Denial of Service. Only users with experimental.remoteFunctions: true who are using the form function and are processing the files array without validation are vulnerable.

Versions of @sveltejs/kit prior to 2.52.2 with remote functions enabled are vulnerable to CPU exhaustion. Malformed form data can cause the server to become unresponsive while processing a request, resulting in denial of service. Only applications using both experimental.remoteFunctions and form are vulnerable.

Versions of @sveltejs/kit prior to 2.52.2 with remote functions enabled can be vulnerable to memory exhaustion. Malformed form data can cause the server process to crash due to excessive memory allocation, resulting in denial of service. Only applications using both experimental.remoteFunctions and form are vulnerable.

Versions of SvelteKit are vulnerable to a server side request forgery (SSRF) and denial of service (DoS) under certain conditions.

The experimental form remote function uses a binary data format containing a representation of submitted form data. A specially-crafted payload can cause the server to allocate a large amount of memory, causing DoS via memory exhaustion.

Unsanitized search param names cause XSS vulnerability. You are affected if you iterate over all entries of event.url.searchParams inside a server load function. Attackers can exploit it by crafting a malicious URL and getting a user to click a link with said URL.

This advisory duplicates another.

This advisory duplicates another.

"Unsanitized input from the request URL flows into end, where it is used to render an HTML page returned to the user. This may result in a Cross-Site Scripting attack (XSS)."

The static error.html template for errors contains placeholders that are replaced without escaping the content first.

In SvelteKit 2 sending a GET request with a body eg {} to a SvelteKit app in preview or with adapter-node throws Request with GET/HEAD method cannot have body. and crashes the app. node:internal/deps/undici/undici:6066 throw new TypeError("Request with GET/HEAD method cannot have body."); ^ TypeError: Request with GET/HEAD method cannot have body. at new Request (node:internal/deps/undici/undici:6066:17) at getRequest (file:///C:/Users/admin/Desktop/reproduction/node_modules/@sveltejs/kit/src/exports/node/index.js:107:9) at file:///C:/Users/admin/Desktop/reproduction/node_modules/@sveltejs/kit/src/exports/vite/preview/index.js:181:26 at call (file:///C:/Users/admin/Desktop/reproduction/node_modules/vite/dist/node/chunks/dep-9A4-l-43.js:44795:7) at next (file:///C:/Users/admin/Desktop/reproduction/node_modules/vite/dist/node/chunks/dep-9A4-l-43.js:44739:5) at file:///C:/Users/admin/Desktop/reproduction/node_modules/@sveltejs/kit/src/exports/vite/preview/index.js:172:6 at …

The SvelteKit framework offers developers an option to create simple REST APIs. This is done by defining a +server.js file, containing endpoint handlers for different HTTP methods. SvelteKit provides out-of-the-box cross-site request forgery (CSRF) protection to its users. The protection is implemented at kit/src/runtime/server/respond.js. While the implementation does a sufficient job of mitigating common CSRF attacks, the protection can be bypassed by simply specifying an upper-cased Content-Type header value. The …

The SvelteKit framework offers developers an option to create simple REST APIs. This is done by defining a +server.js file, containing endpoint handlers for different HTTP methods. SvelteKit provides out-of-the-box cross-site request forgery (CSRF) protection to it’s users. The protection is implemented at kit/src/runtime/server/respond.js#L52. While the implementation does a sufficient job in mitigating common CSRF attacks, the protection can be bypassed by simply specifying a different Content-Type header value.